Control system for accumulation conveyors

ABSTRACT

A device for storing and releasing information regarding articles fed into and out of an accumulation or storage conveyor. As each article enters the conveyor, coded information concerning it is placed in accumulation tubes. This information is in the form of a selected set of conductive and/or non-conductive balls, arranged according to a binary code. At a readout station, coaxial wheels pick up each set of balls in sequence and are indexed so that the balls are aligned with switches operating relays. Each set of balls is thus decoded to give an output signal corresponding to the article being discharged.

United States Patent 191 Ebbert et a1.

[73] Assignee: Ebbert Engineering Company, Troy,

Mich.

[22] Filed: Mar. 7, 1972 [21] Appl. No.: 232,573

Related US. Application Data [63] Continuation-impart of Ser. No. 113,540, Feb. 8,

1971, abandoned.

[52] US. Cl. 317/134, 198/40, 214/11 R [51] Int. Cl...'. E051) 49/00 [58] Field of Search 317/134; 198/40;

[56] References Cited UNITED STATES PATENTS 5/1960 Peras 198/40 X Nov. 20, 1973 Primary ExaminerJ. D. Miller Assistant ExaminerHarry E. Moose, Jr. Attorney-J. King Harness et al.

[57] ABSTRACT A device for storing and releasing information regarding articles fed into and out of an accumulation or storage conveyor. As each article enters the conveyor, coded information concerning it is placed in accumulation tubes. This information is in the form of a selected set of conductive and/or non-conductive balls, arranged according to a binary code. At a readout station, coaxial wheels pick up each set of balls in sequence and are indexed so that the balls are aligned with switches operating relays. Each set of balls is thus decoded to give an output signal corresponding to the article being discharged.

PAIENTEDNUV 20 I975 l CONTROL SYSTEM FOR ACCUMULATION CONVEYORS This application is a continuation-in-part of application, Ser. No. 113,540 filed Feb. 8, l97l,now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to the storing and sequential releasing of information pertaining to articles placed on an accumulation or storage conveyor. Inthis type of conveyor, articles, which may be packages, workpieces, automobile bodies or other items, are fed in a random or prearranged sequence onto one end of the conveyor and are stacked up adjacent the other end, remaining in the same sequence in which they were fed in. The articles are discharged from the exit end of the conveyor with a timing which usually differs from that at which they entered, and which depends on various factors in the total manufacturing or handling process.

The purpose of the information storage and releasing device is to memorize information about each item as it enters the conveyor, and pass said information along at the time said article is released from the conveyor.

2. Description of the Prior Art The closest known prior art comprises electrical shift registers which perform the above described functions purely electrically by shifting information sequentially from stage to stage. One of the main disadvantages of this prior construction isthat, in case of power failure, there is a loss of memory. Moreover, with electrical shift registers it is necessary to increase the number of components, such as relays, in direct proportion to the amount of information being stored. The electrical apparatus furthermore affords no visual indication of the information which has been stored.

BRIEF SUMMARY OF THE INVENTION According to the invention, the information is encoded as groups of balls which are stored by placing them in accumulation tubes as articles pass sequentially onto the accumulation conveyor. Each group comprises conductive and/or non-conductive balls, and as many types of groups are available as are necessary for the types of articles being handled. In the illustrated embodiment a binary system is used so that with a three bit binary arrangement seven different types of articles can be handled. With this arrangement there are three accumulation tubes, and as the first article passes onto the conveyor a first group of balls will be placed in the three accumulation tubes. For example, in this frist group the first ball could be conductive and the second and third non-conductive.

The groups of balls will accumulate in the tubes as the articles are passed onto and accumulated on the conveyor, the groups remaining in the same sequence as the articles. Readout means are provided in the form of coaxial wheels at the exit ends of the accumulation tubes, these wheels being capable of simultaneously receiving the balls of each sequential group and being indexed as each article exits from the conveyor to a position in which its corresponding group is read. Contacts adjacent the wheels will be closed when engaged by a conductive ball but will not be closed by the nonconductive balls. The contacts will control relays so that information stored in the tubes will be decoded for each article in synchronism with the discharge of said article from the conveyor. After readout, the balls will be removed from the wheels back into storage.

In one embodiment, the conductive and nonconductive balls are in the form of two types of spherical members, one made of electrically conductive material and the other of electrically insulative material, or of reduced size, or both. The two types are separately stored adjacent each accumulation tube, and the encoding means for each tube selects one type or the other for each article and places the balls in the accumulation tube where they are aligned in single file.

In a second embodiment, the conductive" and non-conductive balls are all of like diameter but are distinguished from each other by their location in a two-track accumulation tube. The encoding means for each tube selects which track each successive ball enters, the tracks partially overlapping so that the balls are kept in proper sequence. The contacts are aligned with the conductive ball tracks, the wheels carrying the balls so that the conductive balls close the contacts but the non-conductive balls do not.

In the first illustrated embodiment, the ball storage means comprises tubes which receive the balls from the wheels and lead to encoding means in the form of selectively operated plungers which insert them onto the rims of disc type elevators, these elevators carrying the balls to the entrances of the accumulation tubes. In the second embodiment, the plungers operate a gate which guides the balls into one track or the other.

It will thus be seen that the memory function of the unit will remain intact regardless of any electrical power failure which may occur, since the accumulated groups of balls will remain in the tubes. Increased article capacity of the device may be achieved merely by adding to the balls being stored, the capacity of the unit being limited only by the lengths of the accumulation tubes. These tubes may be so constructed that the groups of balls within them are always visible, so that the types and sequence of articles stored on the conveyor may be seen at a glance. For this purpose, the non-conductive balls in the first embodiment may be of a different color and/or size than the conductive balls. The device is extremely simple in its operation and is economical to build and maintain.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view of an accumulation or storage conveyor showing a number of articles thereon and the locations of the encoding and decoding stations;

FIG. 2 is a partially sectioned side elevational view of a portion of the device showing the ball storage tubes, encoding apparatus, elevators, ball accumulation tubes and indexing wheels;

FIG. 3 is a partially sectioned top plan view of the portions of the device shown in FIG. 2, showing the means for guiding the balls from each set of elevators into their corresponding accumulation tube;

FIG. 4 is a fragmentary detailed view of the switch contacts for one of the indexing wheels;

FIG. 5 is a chart showing how a thee bit binary system is used to memorize information for seven types of articles;

FIG. 6 is a circuit diagram for the binary system of FIG. 5;

FIG. 7 is a side elevational view of a second embodirnent of the invention which is basically similar to the first embodiment but in which the conductive and nonconductive balls are distinguished by being placed in one track or the other of the two-track accumulation tube;

FIG. 8 is a fragmentary plan view, partly sectioned, showing the gate and ball return means of the embodiment of FIG. 7;

FIG. 9 is a fragmentary front elevational view showing the manner in which the partially overlapping balls in the tube tracks of the accumulation tube maintain their stacked relation and also showing a readout wheel;

FIG. 10 is a fragmentary elevational view of a portion of the delivery chute showing the passageway means therein;

FIG. 11 is a fragmentary bottom plan view of the chute taken in the direction of the arrow 11 of FIG. 10;

FIG. 12 is a top plan view of an accumulation tube showing the configuration of the partially overlapping tracks; and

FIG. 13 is a fragmentary elevational view of a readout wheel showing its notched configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENT An accumulation or storage conveyor is indicated schematically at 11. This conveyor may be of the endless belt or of any other type which will receive articles 12a, 12b, 12c, etc., at an entrance 13 and discharge them at an exit 14. By articles is meant any units such as packages, workpieces or assemblies. The articles are of different types, varying for example as to size, color, or operation to be performed on them. The articles are placed on conveyor 11 in some sequence, this sequence either being random or prearranged.

The articles do not necessarily exit from the accumulation conveyor with the same timing with which they enter, but they do exit in the same sequence. The exit timing could for example be controlled by a selectively or automatically operable gate 15.

Referring to the embodiment of FIGS. 2 to 5, the means for encoding information about each article as it enters the conveyor comprises a plurality of sets of balls, each set comprising conductive balls 16 and nonconductive balls 17 as seen in FIG. 2. Balls 16 may be fabricated of steel of a predetermined diameter. The manner of making balls 17 non-conductive may be by fabricating them of an electrically insulative material such as nylon, by making them of reduced size as compared with balls 16, or both. Balls of reduced size will not bridge a pair of contacts at the readout station, as described further below.

The conductive balls 16 in each set are stored in a tube 18 whereas the non-conductive balls are stored in a tube 19. These tubes are alongside each other and are downwardly inclined toward their exit end.

The means for encoding information about each article further comprises a pair of plungers 21 and 22 at the exit ends of tubes 18 and 19 respectively, and a pair of ball elevators generally indicated at 23 respectively for receiving balls ejected by plungers 21 and 22. The plungers are normally retracted so that the lowermost balls in the storage tubes are in position for ejection. With the binary system as described below, either a conductive or a non-conductive ball from each set will be ejected onto the corresponding elevator 23 for each article about which information is being encoded.

Any desired means may be used to operate plungers 21 and 22. As an illustration, FIG. 2 shows a switch 24 for plunger 21 and a switch 25 for plunger 22. These switches may be operated either manually or automatically in response to observation of the size, color or other attribute of each article 12 entering conveyor 1 1.

The illustrated elevating means 23 comprises a pair of discs 26 and 27 aligned with plungers 21 and 22 respectively. These discs are coaxially mounted and rotate in unison, being driven continuously by a motor 28 and belt 29. The rims 31 of these discs are of flexible material, having channels 32 for the reception of balls 16 or 17. Similar disc constructions are shown in Ebbert US. Pat. Nos. 3,274,852 and 3,491,718.

The balls picked up by the two discs 26 and 27 of each elevator 23 are discharged into an accumulation tube 33. The means for removing the balls from discs 26 and 27 comprises a pair of ramps 34 disposed in channels 32 adjacent the upper portions thereof and leading to a tapered chute 35, the exit of this chute feeding the upper end of inclined tube 33.

In the illustrated embodiment, a three bit binary system is used to encode information regarding any of seven different types of articles 12. Three accumulation tubes 33, 33 and 33" are therefore provided. These tubes may be fabricated of a transparent material, may have slotted lower ends, or otherwise be provided with means for viewing the balls held therein. Similarly, three elevators 23, 23' and 23" are provided for these tubes. FIG. 5 illustrates the manner in which the seven types of articles would be encoded. Type 1 would be identified by a conductive (white) ball in tube 33, a non-conductive (black) ball in tube 33' and a non-conductive ball in tube 33". An article of Type 2 would be identified by a group of balls comprising a non-conductive ball in tube 33, a conductive ball in tube 33' and a non-conductive ball in tube 33". The manner in which the other types would be encoded is evident from the chart. For each article, a ball will be injected onto either disc 26 or 27 of each elevator, but not onto both at once.

The means for decoding the information stored in accumulation tubes 33 comprises readout wheels 36, 36' and 36" These wheels are mounted on a shaft 37 which is intermittently rotated in angular increments by any appropriate means, such as a conventional indexing clutch generally indicated at 38. The input of slip clutch 38 is provided in the illustrated embodiment by a chain 39 driven from the continuously rotated shaft 40 of elevators 23. A solenoid-operated ratchet release mechanism 41 allows clutch 38 to rotate shaft 37 incrementally each time it is momentarily actuated. Shaft 37 is supported at its outer ends by bearings 42 and 43.

Each wheel 36 is encased in a two part housing 44 which may be fabricated of transparent material. The exit end 45 of each tube 33 is mounted in housing 44 and feeds its balls through a radial passage 46 to the edge of the corresponding wheel 36, which edge is provided with a plurality of circumferentially spaced notches 47. The diameter of each conductive ball 16 is greater than the thickness of wheel 36 whereas the diameter of each non-conductive ball 17 is less than said wheel thickness.

A ball detecting switch generally indicated at 48 is provided for each wheel 36, this switch being spaced by one angular indexing increment from the postion at which a notch 47 will receive a ball 16 or 17. In the illustrated embodiment, the decoding wheels rotate clockwise in FIG. 2 so that switch 48 will be above the position at which the ball is received. The construction of each detecting switch is'seen best in FIG. 4. The switch comprises a pair of contacts 49 and 51 of flat circular shape which are pressed against the opposite sides of the corresponding wheel by springs 42 and 53 respectively. The edges of the contacts are chamfered so that a ball 16, which is thicker than the wheel, will be forced by the wheel between the contacts, closing the circuit between them and causing them to spread apart against the urging of their springs. Guide pins 54 are provided for the contact movement. When a nonconductive ball 17 is brought between the contacts, it will be too small to connect them and the contacts will thus merely'be pressed against the sides of the wheel, which is fabricated of electrically non-conductive material.

Means are provided for returning the decoded balls to their storage tubes, comprising a first relatively small passage 55 in each housing 44 adjacent the lower end thereof and leading to the entrance 56 of the tube 19 which stores the non-conductive balls 17. Only the small non-conductive balls will be able to drop through passage 55. The conductive balls will be carried 'further to a larger passage 57 in housing 44 leading to the entrance 58 of storage tube 18.

In operation, let us assume that the first article is of Type 1. When it enters the conveyor 11 at entrance 13, switches 24, 25' and 25" will be closed, thereby injecting a conductive ball 16 in disc 26 of elevator 23 and non-conductive balls in discs 27 of elevators 23 and 23". These balls will be carried upwardly and introduced into tubes 33, 33' and 33" respectively. The second article being of Type 1 will cause a similar group of balls to be inserted in the accumulation tubes. The third article, of Type 3, will cause tube 33 to receive a conductive ball, tube 33 to receive a conductive ball and 33'. to receive a non-conductive ball. Succeeding articles will cause groups of balls to be inserted in the tubes as shown by the chart of FIG. 5.

When the first article is being discharged from the conveyor, indexing clutch 38 will be actuated, for example by an article-controlled switch 59. This will cause rotation of wheels 36 which will have received the first group of balls. This group will be advanced to switches 48 and will be read out. As each succeeding article is discharged from the conveyor, its corresponding group of balls will be read out. The information as to all the articles will thus be decoded in the same sequence in which the articles are discharged.

FIG. 6 is a circuit diagram showing the manner in which switches 48 may control a binary decoding system. Each switch 46 is shown as controlling a relay 61, and each relay controls a plurality of normally open switches 62 and normally closed switches 63. The switches are so arranged that each combination of conductive and non-conductive balls as shown in the chart of FIG. 5 will result in the corresponding signal 1 through 7. The signals are indicated symbolically at 64 in FIG. 6 and could be of any desired type of visual, auditory or automatic signal or actuator.

FIGS. 7 to 13 illustrate a second embodiment of the invention which is generally similar to the first embodiment but in which two tracks are provided in each accumulation tube, the conductive and non-conductive balls being distinguished from each other by the track in which they are placed, rather than by their size or material. The unit is generally indicated at 101 in FIG.

, 7, this figure illustrating only one accumulation tube generally indicated at 102 and its associated components. It will be understood however that a plurality of accumulation tubes could be used in an arrangement similar to the first embodiment to encode information in a binary system or the like. Tube 102 is of a length sufficient to accumulate the desired number of groups of balls, and is shown as being fabricated of a pair of elongated transparent plastic blocks 103 and 104. These blocks have tracks 105 and l06'respectively, the tracks being formed as grooves having the crosssectional shapes of nearly completed circles with their open sides facing and aligned with each other. Track 106 is adapted to receive conductive balls 107a, whereas track 105 receives non-conductive balls l07b. These balls may be of identical material and are of the same diameter. The balls are held in a storage tube 108 mounted above accumulation tube 102, and are identified with the reference numeral 107 in FIG. 7. Whether a ball 107 becomes a conductive ball 107a or a nonconductive ball 107b is controlled by the selection and delivery means which is generally indicated at 109. This means is best seen in FIGS. 8 to 11 and comprises a gate 111 which rests on a delivery chute 112, the later surmounting accumulation tube 102. Chute 112 has a V-shaped passage as seen best in FIG. 10, with two branches 113 and 114 having openings separated at their upper ends but matching the overlapping tracks 105 and 106 of tube 102 at their lower ends, as seen in FIG. 11.

Gate 111 is of T-shaped construction as seen in FIG. 8, having a pivot 115 adjacent its head and a ball passage 116 at its outer end. A spring 117 is connected at one end to the central leg of gate 111 and is fixed at its other end, this spring yieldably holding the gate in a central position in which passage 116 is above a central platform 118 of chute l 12 between the tops of passages 113 and 114. In this position passage 116 is aligned with tube 108 and will therefore receive a ball 107, but this ball will rest on platform 118.

The encoding means further comprises a pair of solenoid-operated plungers 119 and 121 connected to the oppositely extending arms of gate 111. The solenoids for these plungers are normally de-energized so that the gate is in its central position as shown in FIG. 8. With the binary system as described above, either plunger 119 or 121 for each set of balls 107 will be energized for each article about which information is being encoded, thus dropping a conductive ball 107a into track 106 of accumulation tube 102, or dropping a nonconductive ball 107b into track 105.

The successive balls 107 will be accumulated in tube 102 in the manner shown in FIG. 9. Because of the partially over-lapping nature of the two tracks in the storage tube, the successive balls will be kept in stacked relation regardless of which track they are in, and will therefore be discharged in proper succession as each group of balls is read out.

As in the previous embodiment, the means for decoding the information stored in accumulation tubes 102 comprises a plurality of readout wheels one of which is indicated at 122. Wheel 122 is mounted on a shaft 123 which is intermittently rotated 360 by an indexing clutch 124, controlled for example by articlecontrolled switch 59 (FIG. 1). The surface of wheel 122 has a recess generally indicated at 125 (FIG. 13), this recess matching in cross-sectional shape thetwotrack accumulation tube 102. That is, recess 125 has a pair of partially overlapping portions 126 and 127 which will receive conductive balls 107a and nonconductive balls 1071; respectively and maintain each type of ball in its own plane of rotation. A ball detecting switch 128 is mounted adjacent wheel 122 and is aligned with its recess portion 126 for conductive balls 107a. Thus, as wheel 122 rotates after receiving a ball 107a, switch 128 will be actuated, whereas a ball 107!) will be carried past this switch without effect. With a three-bit binary arrangement as described above, three switches 128, 128' and 128" (the latter two not being shown) corresponding to switches 48, 48' and 48" in FIG. 6 would be provided, with corresponding readout wheels, accumulation tubes and sets of balls 107.

Means are provided for returning the decoded balls of each set to its storage tube 102. This means comprises a trough 129 mounted below wheel 122 into which balls 107 will drop. This trough is inclined downwardly toward the bottom of an elevator generally indicated at 131. The elevator has a track 132 the lower end of which is spaced above the bottom of trough 129 so that balls may singly roll into position beneath the elevator track. An endless chain 133 is mounted on an upper sprocket 134 and a lower sprocket 135, this chain having spaced laterally extending pins 136 which are adapted to engage the underside of a ball 107 beneath track 132 and lift this ball upwardly through the track. For this purpose, track 132 is provided with a slot 137 into which pins 136 will pass, the balls being elevated until they reach the top of tube 108. Track 132 is inclined in such a manner that the balls will roll into storage tube 108 in readiness for re-use.

In operation of the embodiment of FIGS. 7 to 13, gate 111 will normally be in the position shown in FIG. 8. Upon actuation of plunger 119, gate 111 will be shifted counterclockwise in FIG. 8 to permit a ball 107 to drop through chute passage 114 into track 106 of accumulation tube 102, thereby becoming a conductive ball 107a. Simultaneously, balls in the other sets (not shown) will be released to become either conductive or non-conductive balls, thereby making up a group which corresponds to the type of article (see FIG. The balls will drop through accumulation tubes 102 until they reach wheels 122. Upon release of the article from conveyor 11, wheels 122 will be rotated and, if one carries a conductive ball, its switch 128 will be actuated. As the wheels continue to rotate, the balls will drop into troughs 129 and be returned to storage tubes 108 by elevators 131.

This embodiment has several advantages over that previously described in that it eliminates the necessity for two sizes or materials of balls and the consequent requirement for ball sorting. Less balls are required, and since the encoding and selecting means immediately drops a ball into the accumulation tube, delays between the encoding signals and readout will be red'uced.

We claim:

I. In a control system for accumulation conveyors of the type having an entrance station receiving articles of different types in sequence, and a discharge station at which the articles leave in the same sequence, means for encoding information regarding each article as it enters the conveyor comprising a plurality of conductive and non-conductive balls, means for selecting a group of said balls in response to the entry of each article into the conveyor, the arrangement of conductive and non-conductive balls in each group corresponding in code to the type of article entering the conveyor whereby the arrangement of conductive and nonconductive balls in a group is different for each type of article, means storing said encoded information comprising a plurality of accumulation tubes, said selecting means including means delivering each group of balls to said accumulation tubes whereby a single ball from each group will be placed in each accumulation tube and the groups of balls will be stacked in the accumulation tubes in the same sequence as the articles stored in the conveyor, means for decoding the information stored in said accumulation tubes comprising readout means movably mounted at the exits of said accumulation tubes and responsive to the discharge of each article from the conveyor to carry all the balls of the corresponding group simultaneously to a readout station, and a readout circuit responsive to the arrival of each group of balls at the readout station to provide a signal appropriate to the article being discharged.

2. The combination according to claim 1, said encoding means further comprising storage tubes for said conductive and non-conductive balls, said movable readout means comprising wheels having notches receiving said balls from said accumulation tubes, and means receiving said balls after they have passed the readout station and returning them to said storage tubes.

3. The combination according to claim 2, said conductive and non-conductive balls being of different diameters, said ball-receiving means comprising a first relatively small passage receiving the smaller diameter balls and a second relatively large passage receiving the larger diamter balls.

4. The combination according to claim 2, said ball selecting means further comprising plungers at the exit ends of said storage tubes, means selectively actuating said plungers to eject a ball from the exit of the storage tube, said ball delivering means comprising wheels having flexible rims receiving said balls and carrying them to the entrances of the accumulation tubes.

5. The combination according to claim 1, said movable readout means comprising notched coaxial wheels disposed at the exit ends of said accumulation tubes and simultaneously indexable upon the discharge of each article from the conveyor, said conductive balls having a larger diameter than the wheel thickness, said readout circuit including contacts on opposite sides of each wheel at the readout station engageable by the conductive balls, the non-conductive balls having a lesser diameter than the wheel thickness.

6. The combination according to claim 5, said accumulation tubes being downwardly inclined toward their exit ends and being so formed as to permit visual inspection of the groups of balls they contain.

7. The combination according to claim 6, said ball storage means comprising tubes for the conductive and non-conductive balls, and sorting passages adjacent said wheels for returning said conductive and nonconductive balls to their respective storage tubes.

8. The combination according to claim 7, said encoding means comprising plungers at the exit ends of said storage tubes, said ball delivery means comprising coaxial discs with flexible rims receiving balls ejected by said plungers.

9. The combination according to claim 1, said readout circuit further comprising a plurality of relays in series with the contacts adjacent said movable readout means, each relay having normally open and normally closed switches actuated thereby, said last-mentioned switches being connected so as to provide said signals.

10. The combination according to claim 1, said ball delivery means comprising a plurality of pairs of coaxially rotatable discs, means for placing a conductive ball on one disc of each pair and a non-conductive ball on the other disc, means selectively placing either a conductive or non-conductive ball on each pair of discs for each article, there being one accumulation tube for each pair of discs, and means for removing the conductive or non-conductive ball from each disc pair and placing it in the corresponding accumulation tube.

11. The combination according to claim 1, each of said accumulation tubes having conductive and nonconductive tracks, the conductive and non-conductive balls being of the same diameter but distinguished by the track in which they are placed by said selecting means.

12. The combination according to claim 11, said tracks partially overlapping whereby said balls are kept in stacked sequence.

13. The combination according to claim 12, further provided with storage means for the balls being delivered to each accumulation tube, said selecting and delivering means comprising a gate shiftable between a first position permitting a ball to pass from said storage means to the conductive ball track and a second position permitting a ball to pass from said storage means to the non-conductive ball track.

14. The combination according to claim 13, further provided with means yieldably holding said gate in a central position blocking movement of said balls to either track, said selecting means being further provided with solenoid actuatable plungers for moving said gates in either direction from said central position.

15. In an apparatus for encoding and decoding information regarding two types of articles, a plurality of balls, storage means for said balls, an accumulation tube shaped so as to receive balls sequentially at one end in either conductive or non-conductive status, hold them in stacked relation and discharge them sequentially at the other end in the same status, encoding and selecting means responsive to a signal matching the type of article to place a ball from said storage means in said accumulation tube in either conductive or nonconductive status, and decoding means at said other end of the accumulation tube responsive to sequential movement of said articles to release said stacked balls sequentially and sense their conductive or nonconductive status.

16. in an apparatus for encoding and decoding information regarding two types of articles, a plurality of balls, storage means for said balls, means for selecting said balls and storing said encoded information comprising an accumulation tube having a pair of partially overlapping tracks, a gate between said storage means and accumulation tube, means responsive to the types of article for shifting said gate so as to deliver successive balls from said storage means to either track of said accumulation tube, whereby said balls are stacked in the accumulation tube in the same sequence as the signals corresponding to said articles, means for decoding the information stored in said accumulation tube comprising readout means movably mounted at the exit of the accumulation tube, said readout means carrying each ball in succession from the accumulation tube to a readout station, and a readout circuit responsive to the arrival of a ball from one track but not the other at said station to provide a signal appropriate to the article.

17. The combination according to claim 16, further provided with a delivery chute above said accumulation tube with a V-shaped passage, said gate surmounting said delivery chute and being yieldably held in a central position, and means for shifting said gate in either direction from its central position.

18. The combination according to claim 16, further provided with elevator means for returning said balls from said readout station, said elevator means comprising an endless chain with spaced pins, and a track extending along one run of said chain, said pins being engageable with balls at the bottom of said track so as to lift the balls through the track to the top of said storage means. 

1. In a control system for accumulation conveyors of the type having an entrance station receiving articles of different types in sequence, and a discharge station at which the articles leave in the same sequence, means for encoding information regarding each article as it enters the conveyor comprising a plurality of conductive and non-conductive balls, means for selecting a group of said balls in response to the entry of each article into the conveyor, the arrangement of conductive and non-conductive balls in each group corresponding in code to the type of article entering the conveyor whereby the arrangement of conductive and non-conductive balls in a group is different for each type of article, means storing said encoded information comprising a plurality of accumulation tubes, said selecting means including means delivering each group of balls to said accumulation tubes whereby a single ball from each group will be placed in each accumulation tube and the groups of balls will be stacked in the accumulation tubes in the same sequence as the articles stored in the conveyor, means for decoding the information stored in said accumulation tubes comprising readout means movably mounted at the exits of said accumulation tubes and responsive to the discharge of each article from the conveyor to carry all the balls of the corresponding group simultaneously to a readout station, and a readout circuit responsive to the arrival of each group of balls at the readout station to provide a signal appropriate to the article being discharged.
 2. The combination according to claim 1, said encoding means further comprising storage tubes for said conductive and non-conductive balls, said movable readout means comprising wheels having notches receiving said balls from said accumulation tubes, and means receiving said balls after they have passed the readout station and returning them to said storage tubes.
 3. The combination according to claim 2, said conductive and non-conductive balls being of different diameters, said ball-receiving means comprising a first relatively small passage receiving the smaller diameter balls and a second relatively large passage receiving the larger diamter balls.
 4. The combination according to claim 2, said ball selecting means further comprising plungers at the exit ends of said storage tubes, means selectively actuating said plungers to eject a ball from the exit of the storage tube, said ball delivering means comprising wheels having flexible rims receiving said balls and carrying them to the entrances of the accumulation tubes.
 5. The combination according to claim 1, said movable readout means comprising notched coaxial wheels disposed at the exit ends of said accumulation tubes and simultaneously indexable upon the discharge of each article from the conveyor, said conductive balls having a larger diameter than the wheel thickness, said readout circuit including contacts on oppOsite sides of each wheel at the readout station engageable by the conductive balls, the non-conductive balls having a lesser diameter than the wheel thickness.
 6. The combination according to claim 5, said accumulation tubes being downwardly inclined toward their exit ends and being so formed as to permit visual inspection of the groups of balls they contain.
 7. The combination according to claim 6, said ball storage means comprising tubes for the conductive and non-conductive balls, and sorting passages adjacent said wheels for returning said conductive and non-conductive balls to their respective storage tubes.
 8. The combination according to claim 7, said encoding means comprising plungers at the exit ends of said storage tubes, said ball delivery means comprising coaxial discs with flexible rims receiving balls ejected by said plungers.
 9. The combination according to claim 1, said readout circuit further comprising a plurality of relays in series with the contacts adjacent said movable readout means, each relay having normally open and normally closed switches actuated thereby, said last-mentioned switches being connected so as to provide said signals.
 10. The combination according to claim 1, said ball delivery means comprising a plurality of pairs of coaxially rotatable discs, means for placing a conductive ball on one disc of each pair and a non-conductive ball on the other disc, means selectively placing either a conductive or non-conductive ball on each pair of discs for each article, there being one accumulation tube for each pair of discs, and means for removing the conductive or non-conductive ball from each disc pair and placing it in the corresponding accumulation tube.
 11. The combination according to claim 1, each of said accumulation tubes having conductive and non-conductive tracks, the conductive and non-conductive balls being of the same diameter but distinguished by the track in which they are placed by said selecting means.
 12. The combination according to claim 11, said tracks partially overlapping whereby said balls are kept in stacked sequence.
 13. The combination according to claim 12, further provided with storage means for the balls being delivered to each accumulation tube, said selecting and delivering means comprising a gate shiftable between a first position permitting a ball to pass from said storage means to the conductive ball track and a second position permitting a ball to pass from said storage means to the non-conductive ball track.
 14. The combination according to claim 13, further provided with means yieldably holding said gate in a central position blocking movement of said balls to either track, said selecting means being further provided with solenoid actuatable plungers for moving said gates in either direction from said central position.
 15. In an apparatus for encoding and decoding information regarding two types of articles, a plurality of balls, storage means for said balls, an accumulation tube shaped so as to receive balls sequentially at one end in either conductive or non-conductive status, hold them in stacked relation and discharge them sequentially at the other end in the same status, encoding and selecting means responsive to a signal matching the type of article to place a ball from said storage means in said accumulation tube in either conductive or non-conductive status, and decoding means at said other end of the accumulation tube responsive to sequential movement of said articles to release said stacked balls sequentially and sense their conductive or non-conductive status.
 16. In an apparatus for encoding and decoding information regarding two types of articles, a plurality of balls, storage means for said balls, means for selecting said balls and storing said encoded information comprising an accumulation tube having a pair of partially overlapping tracks, a gate between said storage means and accumulation tube, means responsive to the types of article for shifting said gate so as to deliver successive balls from said storage means to either track of said accumulation tube, whereby said balls are stacked in the accumulation tube in the same sequence as the signals corresponding to said articles, means for decoding the information stored in said accumulation tube comprising readout means movably mounted at the exit of the accumulation tube, said readout means carrying each ball in succession from the accumulation tube to a readout station, and a readout circuit responsive to the arrival of a ball from one track but not the other at said station to provide a signal appropriate to the article.
 17. The combination according to claim 16, further provided with a delivery chute above said accumulation tube with a V-shaped passage, said gate surmounting said delivery chute and being yieldably held in a central position, and means for shifting said gate in either direction from its central position.
 18. The combination according to claim 16, further provided with elevator means for returning said balls from said readout station, said elevator means comprising an endless chain with spaced pins, and a track extending along one run of said chain, said pins being engageable with balls at the bottom of said track so as to lift the balls through the track to the top of said storage means. 